Apparatus for severing glass sheets



Oct. 7, 1930. H. F. HITNER APPARATUS FOR SEVERING GLASS SHEETS Filed Dec. 22, 1928 2 Sheets-Shea! l Oct. 7, 1930. H. F. HITNER 1,777,644

APPARATUS FOR SEVERING GLASS SHEETS Filed Dec. 22, 1928 2 Sheexs-Sheet 2 i that when the wire 2 is under tension it lies Patented Oct. 7, 1930 uirso SATES PATENT OFFICE HARRY EITHER, GE OAKMONT, PENNSYLVANIA, ASSIGNOR TO PITTSBURGH PLATE GLASS COMPANY, A CORPORATION OF PENNSYLVANIA.

APPARATUS FOR SEVERING GLASS SHEETS Application filed December 22, 1928. Serial lie. $27,996.

the bar is placed in contact with such sheet. The channel-is of such width that its side walls are spaced away from the edges of the wire a substantial distance, such distance irregular line of fracture which has being preferably several times the width of heretofore been characteristic of the severing the wire. of glass by the use of {in-electrically nested in operation, the device is positioned as wire or ribbon. This irregularity of fracture indicated Figs. 1 and 2 and current supappears to be due to a too greatly localized plied through the wire bringing it to a red line of heating corresponding to the line of few seconds the is heated contact of the heating element with the glass.- sulliciently to permit the cracking off I avoid this condition by providing means operation which is accomplished by appl ing for giving a distribution of heat over a sub a cool or wctted tool to the line of heating stantial area of on each side ofthe rihor by suddenly chilling in some other suitbon or wire, and as a result, the line of free able manner as by the application of air or ture is smooth and regular, approximating in water vapor. This causes the glass to crack these particulars, the line of fracture secured in a. straight true line opposite the longiby scoring the glass with a diamond or wheel. 'tudinal. center line of the wire. I have found Qertain embodiments of the invention are il- "that the use of a channel several times the lustrated in the accompanying drawings, width of the wire contributes to the securing wherein: of a straight true line of fracture, the result Figure l is a longitudinal section on the in these particulars being much better than line II of Fig. 2. T Fig, 2 is a section on in the case where a bar is used whose chanthe line II-H of Fig. 1. And Figs. 2 to 7 nel is only wide enough to receive the wire. are transverse sections through difi'erent The result is also improved by keeping the forms of insulating channel bars. wire out of contact with the glass, although Referring to the drawings, 1 is a channel this'is not an essential, as good results may barcarrying the resistance wire 2, such wire be obtained when the wire actually contacts being in the form of a ribbon extending over with the glass, as indicated in Fig. 6. the rollers 3. 3 and secured at its ends to the Figs. 3 L0 7 indicate modifications. In terminal blocks 4, 4. The blocks arecarried Fig. 3 the wire 9 is carried in a channel bar 7 by spring arms 5,-5, secured to the bar 1 by 10 having a curved cross section. In Figs. means of screws and serving to hold the 4 and 5, the wires 11 and 12 in the bars 13 wire under tension as it expands and conand 14 are respectively circular and semi-cirtracts while being heated and while cooling cular in cross .section. In Fig. 6,.the bar 15 down. Thedeads 6, 6 serve to supply the is increased in width, and the wire 16 con-' electric current for heating the wire. The tacts with the glass. In Fig. 7, the bar 17 bar 1 is preferably of asbestos composition carrying the ribbon wire 18 is of metal and and provides both electrical insulation and is provided with alining 7 of asbestos, or heat insulation. If desired the bar may be other insulating material. If desired, the mode of metal and provided with an asbestos devices may be used in pairs on opposite sides lining 7, as indicated in Fig. I, in which case of the glass sheet to be severed with the wires the bar still provides the necessary electrical exactly opposite and in arallel. This expeand heat insulation and has an added degree dient may be employed to advantage with of strength not present in the bar 1. very thick glass, or when it is desired to The rollers 3, 3 are preferably located so speed up the severing operation. It is also possible to secure the cracking of the glass without the application of cooling means, by merely keeping the device in pos1tion in the glass for a longer period, although the pre- 100 The invention relates to apparatus for se' ering glass sheets by the use of electricity. It has for its objects, the provision of an improved apparatus adapted to prevent the somewhat edges of the channel to the rearof the side 7 2, so that the wire bar, as indicated in Fig. is out of contact'with t e glass sheet 8 when ferred operation includes the application of cooling means, as astep in the operation, as heretofore described.

-What I claim is:

1. In combination in apparatus for severing glass sheets by electricity, a supporting bar of insulating material having a channel in one side, and a resistance Wire mounted in said channel extending longitudinally thereof, said wire having its side edges spaced away a substantial distance from the side walls of the channel.

2. In combination in apparatus for severing glass sheets by electricity, a supporting bar of insulating material having a channel in one side, and a resistance wire mounted in said channel extending longitudinally thereof, said channelhaving a width several times the width of the wire, so that the side edges of the wire are spaced away from the side walls of the channel.

3. In combination in apparatus for severing glasssheets by electricity, a supporting bar of insulating material having a channel in one side, and a resistance wire mounted in said channel extending longitudinally thereof, said wire being out of contact with the walls of said channel.

4. In combination in apparatus for severing glass heets by electricity, a supporting bar of insulating material having a channel in one side, and a resistance wire mounted in said channel extending longitudinally thereof, said wire lying to the rear of the forward edges of said channel and being spaced away from the side and back walls of the channel.

5, In combination in apparatus for severing glass sheets by electricity, a supporting bar of insulating material having a channel in one side, and a roller mounted in said channel at each end thereof, a resistance Wire mounted in said channel and extending over said rollers, and springmeans carried by the supporting bar and engaging the wire for maintaining it under tension, saidwire being spaced away from the back Wall of the channel. I

6. In combination in apparatus for severing glass sheets by electricity, a supporting her of insulating material having a channel in one side, aroller mounted in said channel at each endthereof, a resistance Wire mounted in said channel and extending oversaid rollers, and spring means carried by the supporting bar and engaging the wire for maintaming it under tension, said wire being spaced away from the back and side walls of the channel.

In testimony whereof, I have hereunto subscribed my name this 4th day of Dec,

HARRY F. HITNER 

